Regex Explainer

com.gumballtools/regex-explainerVersion 0.1.0

Explain a regex in plain English and detect catastrophic backtracking risk.

Status

Responds918 msNov 14, 2026, 14:00 UTCAnswered our handshake without sign-in.

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Last checked: Nov 14, 2026, 14:00 UTC
Latency: 918 ms
Remotes responding: 1 of 1
Sign-in: No sign-in
Hosting: Hosted outside the EU (detected)
Registry data as of: Nov 14, 2026, 22:14 UTC

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Connect

Streamable HTTP

https://regex-explainer.gumballtools.com/api/mcpResponds918 msNov 14, 2026, 14:00 UTC

No sign-in

Claude Code

claude mcp add --transport http regex-explainer https://regex-explainer.gumballtools.com/api/mcp

Claude Desktop and claude.ai

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Settings > Connectors > Add custom connector
Name: regex-explainer
Remote MCP server URL: https://regex-explainer.gumballtools.com/api/mcp

Cursor

{
  "mcpServers": {
    "regex-explainer": {
      "url": "https://regex-explainer.gumballtools.com/api/mcp"
    }
  }
}

VS Code

code --add-mcp '{"name":"regex-explainer","type":"http","url":"https://regex-explainer.gumballtools.com/api/mcp"}'

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Tools

1 tools

Tools of Regex Explainer
	Description		Read-only	Idempotent	Open world
`explain_regex`Explain a regular expression in plain English and detect the failure modes that make patterns dangerous rather than merely wrong. Use this whenever a regex needs to be read, reviewed, or verified — and ALWAYS before putting a pattern somewhere it will run against untrusted input. The critical check is catastrophic backtracking: a pattern like (a+)+$ is three characters longer than a safe equivalent, looks harmless, and takes minutes of CPU on a 30-character input that almost matches. That makes it a denial-of-service vector. Whether a pattern is vulnerable depends on whether nested quantifiers can match the same characters in more than one way, which is a structural property that is unreliable to judge by reading. It also flags: missing anchors (an unanchored validator accepts any string that merely CONTAINS a valid value), unescaped dots, character ranges like [A-z] that span punctuation, alternation precedence mistakes where an anchor applies to only one branch, and constructs JavaScript does not support. Input: `pattern` accepts either a bare pattern or a full /pattern/flags literal. JavaScript syntax; PCRE-only constructs are reported as unsupported rather than guessed at. Returns: `summary` (one sentence), `steps` (an ordered walkthrough), `warnings` (each with a code, severity, detail, and fix), `flagNotes`, capture group counts and names, and `hasBlockingIssue` — check that flag first. If the pattern cannot be parsed it returns an error naming the position, rather than a plausible-looking explanation of something else.	Explain a regular expression in plain English and detect the failure modes that make patterns dangerous rather than merely wrong. Use this whenever a regex needs to be read, reviewed, or verified — and ALWAYS before putting a pattern somewhere it will run against untrusted input. The critical check is catastrophic backtracking: a pattern like (a+)+$ is three characters longer than a safe equivalent, looks harmless, and takes minutes of CPU on a 30-character input that almost matches. That makes it a denial-of-service vector. Whether a pattern is vulnerable depends on whether nested quantifiers can match the same characters in more than one way, which is a structural property that is unreliable to judge by reading. It also flags: missing anchors (an unanchored validator accepts any string that merely CONTAINS a valid value), unescaped dots, character ranges like [A-z] that span punctuation, alternation precedence mistakes where an anchor applies to only one branch, and constructs JavaScript does not support. Input: `pattern` accepts either a bare pattern or a full /pattern/flags literal. JavaScript syntax; PCRE-only constructs are reported as unsupported rather than guessed at. Returns: `summary` (one sentence), `steps` (an ordered walkthrough), `warnings` (each with a code, severity, detail, and fix), `flagNotes`, capture group counts and names, and `hasBlockingIssue` — check that flag first. If the pattern cannot be parsed it returns an error naming the position, rather than a plausible-looking explanation of something else.	Not declared	Yes	Not declared	No

Details

Registry status: Active
Published: Sep 5, 2026
Updated: Sep 5, 2026
Website: https://regex-explainer.gumballtools.com/⁠ (opens in a new tab)
Repository: https://github.com/bwalvoord/gumball⁠ (opens in a new tab)
Categories (suggested): Developer toolsSuggested categories are assigned automatically from the registry text and may be wrong. Verified operators can correct them.
GDPR: Not declared

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